Vehicle Mass and Drag Determination via Accelerometer
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Solution Overview
Problem
Modern vehicles face challenges in dynamically determining their mass and other characteristics without adding additional sensors, leading to sub-optimal powertrain control due to the use of constant mass values, which increases complexity and cost.
Innovation Solution
The system utilizes a vehicle's accelerometer to calculate mass, drag force coefficients, and driving surface inclination using existing sensors and torque models, eliminating the need for specialized sensors by measuring longitudinal acceleration and drive force, and applying methods like least squares regression to determine these values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional mass detection sensors are installed to dynamically measure vehicle mass, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The accelerometer, originally designed for measuring longitudinal acceleration, is repurposed to also determine vehicle mass by analyzing acceleration patterns during coastdown events. This multi-functional use of existing hardware eliminates the need for dedicated mass sensors while providing dynamic mass measurement capability.
Solution Approach 2:
The vehicle's existing accelerometer serves dual purposes: its primary function for acceleration measurement and an additional function for mass determination. The system uses the accelerometer's own measurements during coastdown events to calculate mass, allowing the single sensor to service multiple measurement needs without requiring additional specialized sensors.
2Manufacturing precision
If additional mass detection sensors are installed to dynamically measure vehicle mass, then powertrain control accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The accelerometer performs both its original acceleration measurement function and an additional mass measurement function, eliminating the need for separate mass detection sensors and reducing overall sensor system cost while maintaining powertrain control accuracy.
Solution Approach 2:
The system determines mass by analyzing changes in acceleration parameters during coastdown events rather than using direct mass measurement sensors. This parameter-based indirect measurement approach reduces hardware costs while providing the necessary mass data for accurate powertrain control.
3Device complexity
If a constant mass value is used for powertrain calculations, then device complexity is reduced, but powertrain control performance deteriorates
Solution Approach 1:
The system transitions from using a static constant mass value to dynamically determining mass through coastdown events. The accelerometer continuously monitors acceleration during coastdown, and the system updates mass calculations as needed, allowing the mass parameter to adapt dynamically to actual vehicle loading conditions while using only existing sensors.
Solution Approach 2:
The system uses feedback from the accelerometer during coastdown events to continuously update the vehicle mass estimate. This feedback mechanism allows the powertrain control system to adapt to changing vehicle mass conditions without requiring additional sensors or complex hardware modifications.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for dynamic and accurate determination of vehicle mass and other characteristics, enhancing powertrain control efficiency without increasing vehicle complexity or cost, and can be integrated into existing vehicle systems.
Implementation Method 1
The vehicle's mass, drag force coefficients and inclination are determined using signals input from the vehicle's accelerometer
Data Source
AI summary
A method and system of determining a vehicle's driving characteristics such as the vehicle mass, drag force coefficients and driving surface inclination. The vehicle's mass, drag force coefficients and inclination are determined using signals input from the vehicle's accelerometer.